Airbag Apparatus And Motorcycle Having The Same

ABSTRACT

A technique is provided effective in protecting the tether that connects the airbag to the vehicle in an airbag apparatus mounted to a motorcycle. In one form, an airbag apparatus mounted to a motorcycle has a bent portion having a smooth surface at a position where webbings for tethering an airbag to the vehicle body is in contact with a retainer.

FIELD OF THE INVENTION

The present invention relates to a technique of constructing an airbagapparatus to be mounted to a motorcycle.

BACKGROUND OF THE INVENTION

There have been various known techniques of restraining occupants ofmotorcycles with airbag apparatuses. For example, known techniquesincludes a technique of restraining an occupant with an airbag inflatedby inflation gas in a frontal collision (e.g., refer to JapaneseUnexamined Patent Application Publication No. 2003-327182). The airbagapparatus disclosed in Japanese Unexamined Patent ApplicationPublication No. 2003-327182 has a structure in which a prefolded airbagis housed in a housing and the airbag is connected to the vehicle body(body frame) with a tether.

In the airbag apparatus described in Japanese Unexamined PatentApplication Publication No. 2003-327182, the tether extends from theinterior of the housing to the exterior. With this arrangement, when thevehicle vibrates during traveling, when the tether is withdrawn from thehousing for maintenance, and when the tether extends from the loosestate with the deployment of the airbag, the tether may be worn outlocally due to contact with the metallic member of the housing.

SUMMARY OF THE INVENTION

The present invention has been made in view of the problem. Accordingly,it is an object of the invention to provide a technique effective inprotecting the tether that joins the airbag to the vehicle in an airbagapparatus mounted to a motorcycle.

In order to achieve the above object, the invention described in theclaims is provided. Typically, the invention can be applied inconstructing airbag apparatuses to be mounted to various motorcycles. Inthis specification, “a motorcycle,” a typical example of vehicles,includes various saddle-type vehicles that an occupant straddles, suchas touring motorcycles having a fuel tank in front of an occupant seatand motor scooters having a space between an occupant seat and ahandlebar-supporting head pipe. In addition to the motorcycles, the“motorcycle” includes vehicles that occupants straddle and having threeor more running wheels (e.g., three-wheel motorbikes for use in homedelivery service and three- or four-wheel buggies for bad roads) andvehicles that occupants ride on and running by sledges or caterpillars,such as snow mobiles.

A first form of the present invention for solving the above-describedproblem is an airbag apparatus mounted to a motorcycle and includes atleast gas generation device, an airbag, a housing, a tether, and asmoothing device.

The gas generation device of the invention is a device for generatingairbag inflation gas. The airbag of the invention restrains an occupantby deploying into an occupant restraining region in front of theoccupant by the airbag inflation gas generated by the gas generationdevice in a frontal collision of the motorcycle. Here the “frontalcollision” indicates that the motorcycle collides with a running orstill front object such as a vehicle, a pedestrian, an obstacle or thelike. The “occupant restraining region” is defined as a space extendingin the direction of the forward movement of an occupant who is movingahead of the motorcycle by a kinetic energy during a frontal collision,for restraining the occupant who is flung ahead of the motorcycle by thekinetic energy.

The housing of the invention houses an airbag. The housing is typicallya bottomed-box-shaped retainer. The housing may be constructed of theretainer and a cover (module cover) that covers an airbag opening at thetop of the retainer.

The tether of the invention is an elongated member extending between theinterior and the exterior of the housing so as to tether the airbag inthe housing to the vehicle body. For the tether, an elongated memberhaving a strength sufficient to retain the airbag to the vehicle bodycan be used. The “elongated member” of the invention broadly includes abelt and a strap, typically a belt-like tether made of resin fibers orthe like. This tether has the function of restricting the forwardmovement of the airbag by retaining the airbag to the vehicle body bythe tension upon completion of deployment of the airbag. The number ofthe tethers of the invention may be varied to one or more as necessary.

The tether with the above structure extends from the interior of thehousing to the exterior. With this arrangement, when the vehiclevibrates during traveling, when the tether is withdrawn from the housingfor maintenance, or when the tether extends from the loose state withthe deployment of the airbag, the tether may cause local wear due tocontact with the metallic member of the housing. Accordingly, the airbagapparatus of the invention includes a smoothing device.

The smoothing device smoothes the sliding between the tether and ametallic contact of the housing in contact with the tether. Here the“metallic contact of the housing” may be disposed at the housing itselfor at another separate member mounted to the housing. The use of thesmoothing device can reduce the sliding resistance (frictionalresistance) between the metallic hard contact and the tether to enablesmooth sliding, thereby preventing the wear of the tether. The smoothingdevice may adopt a structure in which a material of low slidingresistance (frictional resistance) to the tether is disposed between thetether and the contact, a structure in which an arcuate smooth contactis used, a structure in which a contact having a large surface area isused, or a structure in which the contact is subjected to surfacegrinding, thereby decreasing the sliding resistance (frictionalresistance) to the tether. The smoothing device of the invention can bedisposed to at least one of the tethers and the contact of the housing.

Thus the arrangement of the airbag apparatus according to the first formof the invention can improve the protection of the tether for connectingthe airbag to the vehicle body.

A second form of the invention for solving the above-described problemis an airbag apparatus wherein the smoothing device of the first form isan arcuate contact formed of a folded metal portion of the housing. Thatis, the metallic folded portion of the housing serves as the contactwith the tether and the arcuate surface for smoothing the sliding of thetether. The arcuate surface is made smooth to enable the movement of thetether while maintaining surface contact with the tether in the tethermoving direction when the tether moves relative to the housing with thevibration of the vehicle, the withdrawal of the tether for maintenance,or airbag deploying motion. At that time, the curvatures of the tetherand the arcuate surface are substantially equal at the contact betweenthe tether and the arcuate surface. In other words, the arcuate surfaceserves to guide the tether relative to the housing while maintaining thesurface contact so as to agree the curvature of the tether with that ofthe arcuate surface. Here the “arcuate surface” broadly includes arcuatesurfaces of various curvatures which correspond to part of a circle oran ellipse.

With this structure, a smoothing device can be made by folding thehousing itself. This can simplify the structure of the smoothing deviceand reduce the number of components of the smoothing device.

A third form of the invention for solving the above-described problem isa motorcycle with an airbag apparatus according to the first or secondform of the invention.

Thus, the third form of the invention provides a motorcycle mounted withan airbag apparatus in which protection of the tether for connecting theairbag to the vehicle body is improved.

In the airbag apparatus to be mounted to a motorcycle according to thepresent invention, protection of the tether can be improved by using anelongated tether extending between the interior and exterior of thehousing so as to tether the airbag in the housing to the vehicle body;and a smoothing device that smoothes the sliding between the tether anda metallic contact of the housing in contact with the tether.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a motorcycle 100 according to an embodiment of“a motorcycle” of the invention, showing a state in which an airbagapparatus 120 is mounted to the motorcycle 100.

FIG. 2 is a diagram showing the motorcycle 100 in FIG. 1 as viewed fromthe top thereof.

FIG. 3 is a sectional view of the motorcycle 100 in FIG. 2 taken alongline A-A.

FIG. 4 is a fragmentary enlarged view of FIG. 3.

FIG. 5 is a cross sectional view of the motorcycle 100 taken along lineB-B in FIG. 2.

FIG. 6 shows the structure of folded portions 143 of webbings 140 of theembodiment.

FIG. 7 shows a module cover 130 and a retainer 123 of the embodimentviewed from the top of the vehicle.

FIG. 8 shows the module cover 130 and the retainer 123 from the rear ofthe vehicle.

FIG. 9 shows the module cover 130 and the retainer 123 from the side ofthe vehicle.

FIG. 10 shows a section taken along line C-C in FIG. 7.

FIG. 11 shows a section taken along line D-D in FIG. 7.

FIG. 12 shows the retainer 123 of the embodiment viewed from the top ofthe vehicle.

FIG. 13 shows a section taken along line E-E in FIG. 12.

FIG. 14 is an enlarge view of part F in FIG. 13.

FIG. 15 shows the state of an airbag 121 of the airbag apparatus 120 atthe start of inflation.

FIG. 16 shows the airbag 121 at the middle of inflation.

FIG. 17 shows the airbag 121 at the completion of inflation, as viewedfrom the side of the vehicle.

FIG. 18 shows the airbag 121 at the completion of inflation, as viewedfrom the top of the vehicle.

FIG. 19 shows another embodiment of the bent portion 124 of FIG. 4.

FIG. 20 shows still another embodiment of the bent portion 124 of FIG.4.

FIG. 21 shows yet another embodiment of the bent portion 124 of FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described specificallywith reference to the drawings. Referring first to FIGS. 1 and 2, theentire structure of a motorcycle 100 will be described. FIG. 1 is a sideview of the motorcycle 100 according to an embodiment of the invention,showing a state in which an airbag apparatus 120 is mounted to themotorcycle 100. FIG. 2 shows the motorcycle 100 of FIG. 1, viewed fromthe top of the vehicle. The motorcycle 100 of the embodiment is anexample of “a motorcycle” or “a motorcycle vehicle” of the invention.

Referring to FIGS. 1 and 2, the motorcycle 100 is what is called atouring motorcycle and mainly comprises a body frame 101 including anengine and a main frame; a seat 103 that occupants can straddle;handlebars 104; a front wheel 111; and a rear wheel 112.

A region above the body frame 101 of the motorcycle 100 and in front ofan occupant seated in the seat 103 is defined as an occupant restrainingregion 150 in the event of a frontal collision of the motorcycle 100.The “frontal collision” in the embodiment indicates that the motorcycle100 collides with various front objects (e.g., a vehicle, a pedestrian,an obstacle, and a guardrail, not shown for convenience sake). The“occupant restraining region 150” of the embodiment corresponds to “anoccupant restraining region” of the invention, which is defined as aspace extending in the direction of the forward movement of an occupantseated in the seat 103 during a frontal collision, for restraining theoccupant who is flung ahead of the motorcycle by a kinetic energy.

A front portion 102 of the body frame 101 includes a headlight, variousmeters, switches, a windshield, and the like. A fuel tank 106 isdisposed at the front of a body component 105 between the front portion102 and the seat 103. The airbag apparatus (also referred to as anairbag module) 120 is disposed in front of the fuel tank 106. Webbingcovers 107 for covering a pair of right and left webbings 140 that is acomponent of the airbag apparatus 120 are disposed on both sides of thefuel tank 106. The webbings 140 cannot or hardly be seen from theexterior owing to the covering by the webbing covers 107 in a normalstate in which the airbag apparatus 120 is inoperative. The webbings 140will be specifically described later in the description of the airbagapparatus 120.

The structure of the airbag apparatus 120 of this embodiment will bespecifically described with reference to FIGS. 3 to 14. The airbagapparatus 120 is disposed so as to face the occupant restraining region150 for the occupant seated in the seat 103. The airbag apparatus 120corresponds to “an airbag apparatus” of the invention.

FIG. 3 is a sectional view of the motorcycle 100 in FIG. 2 taken alongline A-A; FIG. 4 is a fragmentary enlarged view of FIG. 3; and FIG. 5 isa cross sectional view of the motorcycle 100 taken along line B-B inFIG. 2. As shown in FIGS. 3 and 4, the airbag apparatus 120 mainlycomprises an airbag 121, an inflator 122, a retainer 123, a module cover130, and the webbings 140.

The airbag 121 is housed in the retainer 123 in a predetermined foldedstate (like a bellows or a roll). In FIG. 3, the direction of theinflation (deployment) of the airbag 121 is indicated by arrow 10. Theairbag 121 is made of a material similar to airbag cloth for cars. Theairbag 121 corresponds to “an airbag” of the invention.

The inflator 122 is a gas supply device that generates airbag inflationgas and supplies it into the airbag 121 at a vehicle collision so thatthe airbag 121 in a folded state inflates while deploying from theretainer 123. The inflator 122 corresponds to “an inflator” of theinvention.

The retainer 123 is shaped like a bottomed box having at least an airbaghousing 123 a for the airbag 121 and an inflator housing (recess) 123 bfor the inflator 122. The retainer 123 houses the airbag 121 and has anopening (airbag opening) at the top, which allows the deployment of theairbag 121. The retainer 123 is typically formed by pressing a metallicmaterial. The retainer 123 corresponds to “a housing that houses theairbag” of the present invention. A combination of the retainer 123 andthe module cover 130 may serve as “a housing that houses the airbag” inthe present invention.

In this embodiment, the webbings 140, to be described later, extend fromthe interior of the retainer 123 to the exterior. Accordingly, thewebbings 140 may be locally worn down by contact with the retainer 123when the vehicle vibrates during traveling, when the webbings 140 areretracted from the housing for maintenance, and when the webbings 140are extended from a loose state with the deployment of the airbag 121.The retainer 123 of the embodiment therefore has a bent portion 124 atthe portion with which the webbing 140 may come into contact. The bentportion 124 has a smooth surface (a smooth surface 124 a in FIG. 4) atthe upper end of the metal-plate retainer 123. The smooth surface 124 ais formed by folding back (bending) the upper end (plate end) of theretainer 123. The smooth surface 124 a is an arc-shaped smooth surface(arcuate surface) corresponding to part of a circle or ellipse and assuch, and it has a function of reducing the sliding resistance betweenthe contact portion of the retainer 123 and the webbings 140 to enablesmooth sliding.

Specifically, the smooth surface 124 a is shaped to allow the movementof the webbings 140 while maintaining surface contact with the webbings140 in the moving direction of the webbings 140 when the vehiclevibrates, when the webbings 140 are retracted for maintenance, and whenthe webbings 140 are moved with the deployment of the airbag 121. Atthat time, the curvatures of the webbings 140 and the smooth surface 124a are substantially equal at the region where the webbings 140 and thesmooth surface 124 a are in contact. In other words, the smooth surface124 a serves to guide the webbings 140 relative to the retainer 123while maintaining the surface contact so as to agree the curvature ofthe webbings 140 with the curvature of the smooth surface 124 a.

This arrangement can prevent the wear of the webbings 140 made of, e.g.,fibers due to contact with the metallic retainer 123 by use of thesmooth surface 124 a of the bent portion 124. Since, in this embodiment,the retainer 123 itself in contact with the webbings 140 has the smoothsurface 124 a, the smoothing structure is simplified, thus decreasingthe number of components. It is preferable to increase the surface areaof the smooth surface 124 a of the bent portion 124 to thereby dispersethe local frictional force to the webbings 140. The upper end of theretainer 123 corresponds to “a metallic contact of the housing” and thesmooth surface 124 a (the bent portion 124) of the retainer 123corresponds to the smoothing device and arcuate contact of the presentinvention. A more detailed description of the retainer 123 will be givenhereinlater.

The module cover 130 covers the opening (airbag opening) of the retainer123 from above to thereby cover the airbag 121, and has at least a topplate 131 and an erect portion 132. The module cover 130 is typicallymolded of a resin material.

The top plate 131 extends substantially horizontally in the direction ofthe opening surface at the airbag opening region of the retainer 123 tothereby form the upper surface of the airbag apparatus 120. The erectportion 132 is a plate portion and extends vertically from the lowersurface (back) of the top plate 131 toward the retainer 123 to cross theextending direction of the top plate 131. The erect portion 132 issecured to the retainer 123 with fixing portions (fixtures 128, to bedescribed later) of the retainer 123 to thereby join the module cover130 and the retainer 123 together.

Referring to FIG. 4, a pair of right and left through holes 134 thatcommunicate the interior of the module cover 130 with the exterior isprovided at the part of the rising portion 132 adjacent to the rear ofthe vehicle (adjacent to the occupant). The webbings 140, to bedescribed later, can extend from the interior to the exterior of themodule cover 130 through the through holes 134. When the top plate 131receives the deploying force of the airbag 121 at a vehicle collision,the module cover 130 is torn open along a tear line 133 and two tearlines 135, to be described later, of the erect portion 132, to releasethe covering of the opening (airbag opening) of the retainer 123. Thisenables the deployment of the airbag 121. A more detailed description ofthe module cover 130 will be given hereinlater.

In this embodiment, the airbag 121 is tethered to the body of themotorcycle 100 with the pair of right and left elongated webbings 140.The webbings 140 are formed like a belt made of the same material asthat of car seatbelts (resin fiber belt) or the same material as that ofairbag cloth. The webbings 140 may be formed like a strap instead of thebelt. A first end 141 of each webbing 140 is stitched to the airbag 121and a second end 142 is joined to a fastener (a fastener 108 in FIGS. 1and 2) on the body. In other words, the webbings 140 extend in the frontand back direction in parallel at two positions between the airbagapparatus 120 and the vehicle body. As shown in FIGS. 4 and 5, when theairbag apparatus 120 is in an inoperative state, the webbings 140 extendin the housing space between the webbing covers 107 and the bodycomponent 105, and the upper parts of the webbings 140 are covered withthe webbing covers 107. The webbings 140 correspond to “tethers” of theinvention.

Since the webbings 140 are in an irregularly loose state while theairbag is housed, the extending motion of the webbings 140 from theloose state with the deployment of the airbag at a frontal collision ofthe vehicle may exert an influence on a desired deploying motion of theairbag 121. Therefore, in the embodiment, each webbing 140 has a foldedportion 143 below the webbing cover 107 so as to keep the looseness ofthe webbing 140 in a predetermined bunched state before the activationof the airbag apparatus 120 (while the airbag 121 is housed). The looseportions at the folded portions 143 of the webbings 140 are piled(folded back). The opposing surfaces of the loose portion are providedwith a hook-and-loop fastener 144 that can temporarily hold the looseportion in the folded state (the predetermined bunched state).

The hook-and-loop fastener 144 has a known structure, which is adetachable tape using a pile structure and is the so-called Velcrofastener. Specifically, the hook-and-loop fastener 144 has smallmushroom-shaped expanded portions (or hooks) on one surface, and loopson the other surface. When the two surfaces are put together, themushroom portions (or hooks) are caught (hooked) in the loops, so thatthey easily stick to each other; when they are pulled from each other,the mushrooms come out from the loops, so that they are easily peeledfrom each other.

With such a structure, the folded (bunched) state of the folded portion143 while the airbag is housed can temporarily be kept by thehook-and-loop fastener 144. On the other hand, when a predeterminedtensile load is applied to the webbings 140 at the deployment of theairbag 121, the retaining force by the hook-and-loop fastener 144 isreleased, so that the folded (bunched) state of the folded portion 143is released.

FIG. 6 shows the structure of the folded portions 143 of the webbings140 of the embodiment. As shown in FIG. 6, in this embodiment, thefolded portions 143 are disposed substantially symmetrically. Thisarrangement can reduce the looseness of the webbings 140 while theairbag is housed and makes the loads of the right and left webbings 140,which extend at the deployment of the airbag 121, on the airbag 121substantially equal, thus being effective in deploying the airbag 121laterally equally.

For the webbing holding structure, the embodiment can employ anotherwebbing holding device other than the hook-and-loop fastener 144,provided that the folded state of the folded portions 143 cantemporarily be held. For example, the folded state of the foldedportions may be temporarily kept by a structure in which the foldedportions are stitched up with a tear seam or a structure in which thefolded portions are wound by an adhesive tape or the like. At that time,an appropriate structure can be adopted for temporarily holding theloose portions of the webbings 140 in a predetermined folded state (apredetermined folded-back state) or in a predetermined wound state witha webbing holding device.

Referring to FIGS. 7 to 11, a more detailed description of the modulecover 130 will be given. FIG. 7 shows the module cover 130 and theretainer 123 of the embodiment viewed from the top of the vehicle; FIG.8 shows them from the rear of the vehicle; FIG. 9 shows them from theside of the vehicle; FIG. 10 shows a section taken along line C-C ofFIG. 7; and FIG. 11 shows a section taken along line D-D of FIG. 7.

As shown in FIGS. 7 to 9, the erect portion 132 of the module cover 130of the embodiment has a tear line 133 along the outer periphery thereofadjacent to the rear of the vehicle (adjacent to the occupant), and twotear lines 135 along the inner periphery on both sides. In thisembodiment, the tear lines 133 and 135 are provided not to the top plate131 but to the erect portion 132. Accordingly, even if a load such as anoccupant or a burden is applied from above the module cover 130, theload is not directly applied to the tear lines 133 and 135, thuspreventing the module cover 130 from being torn open along the tearlines 133 and 135. The embodiment may have a continuous tear line fromthe erect portion 132 of the module cover 130 across another portion ofthe top plate 131.

The disposition of the through holes 134 on the tear line 133streamlines the structure because the installation locations are shared.

As shown in FIGS. 10 and 11, the tear lines 133 and 135 are formed byproviding triangular cutouts in the erect portion 132. Thus threecontinuous grooves with a predetermined depth, or thin portions of asubstantially even thickness within the thickness of the erect portion132 are formed in the erect portion 132 adjacent to the rear and bothsides of the vehicle. Thus the tear lines 133 and 135 are also referredto as “linear grooves,” “thin portions,” or “fragile portions” having alinear groove of a predetermined depth. Since the thickness at the tearlines 133 and 135 (the thickness of the thin portions) is appropriatelyset on the basis of the specifications of the airbag 121, such as adeploying force, the module cover 130 can be smoothly torn open alongthe tear lines 133 and 135 of the erect portion 132 by the deployingforce of the airbag 121 in the event of a vehicle accident, so that theportion of the module cover 130 above the tear lines 133 and 135 deploystoward the front of the vehicle with the portion of the erect portion132 adjacent to the front of the vehicle as the hinge. At that time, theportion of the cover lower than the tear lines 133 and 135 is secured tothe retainer 123 when the tear lines 133 and 135 are torn open or theairbag 121 deploys such that fasteners 128 on the retainer 123 arehooked in the through holes of the erect portion 132 or fixed withrivets (refer to FIG. 8). The tear lines may be continuous grooves of aspecified depth disposed at regular intervals, continuous perforations,or continuous slits disposed at regular intervals, instead of thecontinuous groove of a predetermined depth.

The cutoffs of the tear lines 133 and 135 of the embodiment may beformed in dies during the molding of the module cover, or alternatively,may be formed by post machining such as laser beam machining orultrasonic machining after the molding of the module cover. The sectionsof the tear lines 133 and 135 may be varied to a triangle, a semicircle,etc. as appropriate. The tear line 133 may be formed along the innercircumference of the erect portion 132 adjacent to the rear of thevehicle (adjacent to the occupant), while the tear lines 135 may beformed along the outer circumference of the both sides of the erectportion 132.

Referring then to FIGS. 12 to 14, a more detailed structure of theretainer 123 will be presented. FIG. 12 shows the retainer 123 of theembodiment viewed from the top of the vehicle; FIG. 13 shows a sectiontaken along line E-E of FIG. 12; FIG. 14 shows an enlarged view of partF in FIG. 13.

As shown in FIGS. 12 and 13, the retainer 123 of the embodiment has apair of hole-like first through portions 125 at an inflator housing 123b at the bottom of the retainer 123, a pair of slit-like second throughportions 126 at the right and left ends, and a pair of slit-like thirdthrough portions 127 at the front and rear ends. The first throughportions 125, the second through portions 126, and the third throughportions 127 extend vertically through the bottom of the retainer 123,and have a function of draining water entering the retainer 123 to theoutside of the retainer 123. Thus, the water entering the retainer 123is continuously or intermittently drained through the first throughportions 125, the second through portions 126, and the third throughportions 127 to the outside of the retainer 123 by gravitation.

Since the housing like the retainer 123 of the embodiment is a bottomedbox having an airbag opening on the top, liquid such as water or oil maybe prone to enter or reside in the housing through the periphery of theairbag opening even with high tightness. Particularly, generalmotorcycles have an airbag apparatus exposed to the outside of thevehicle body in contrast to cars, so that such a problem may bepronounced under the influence of rain, cleaning water, and humidity.Accordingly, the embodiment has the first through portions 125, thesecond through portions 126, and the third through portions 127 fordrainage at the bottom of the retainer 123. Of course, liquids such asoil entering the retainer 123 other than water may be drained from theretainer 123 through the first through portions 125, the second throughportions 126, and the third through portions 127. The through portionfor drainage may be holes, slits, mesh, a punching plate, or otheropenings. In this embodiment, the installation locations and the numberof installation locations of the draining through portion may be variedas appropriate.

The first through portions 125 are located at the recessed inflatorhousing 123 b, which is the lowest of the bottom of the retainer 123.More specifically, the bottom of the retainer 123 has a downward slope(curved slope) toward the first through portions 125. Accordingly, thewater entering the retainer 123 is collected to the first throughportions 125 along the slope of the inflator housing 123 b, and issurely drained through the first through portions 125 to the outside ofthe retainer 123.

On the other hand, the second through portions 126 have the function ofdraining the water, which enters the retainer 123 and resides at theright and left ends thereof to the outside of the retainer 123 when themotorcycle 100 is parked at an angle using a side stand, or when thevehicle body tilts laterally during driving. Furthermore, as shown inFIG. 14, the bottom of the retainer 123 decreases in height toward thesecond through portions 126 (at an inclination angle θ). In other words,the bottom of the retainer 123 has a downward slope (linear slope)toward the second through portions 126. Thus, the water entering theretainer 123 is collected to the second through portions 126 along theslope of the bottom of the retainer 123 when the vehicle body tilts andeven when the vehicle body is in a horizontal position, and is surelydrained through the second through portions 126 to the outside of theretainer 123. Particularly, since the second through portions 126 aredisposed at the right and left ends of the retainer 123, the secondthrough portions 126 easily become the lowest of the bottom of theretainer 123 when the motorcycle tilts to the right or left side, thusincreasing the draining function. Motorcycles tilt to the right or leftwhen parked at a rightward or leftward inclination, or when tilted tothe right or left during driving on a right or left curve. Theinclination angle θ of the bottom of the retainer 123 may beappropriately set according to the specifications of the retainer 123.

Furthermore, the third through portions 127 have the function ofdraining the water intruding into the retainer 123 and residing at thefront and rear end. For example, the motorcycle 100 tilts on an upwardslope or downward slope run because the front of the body becomes higheror lower than the rear. In this embodiment, the third through portion127 on the front or rear side easily becomes the lowest of the bottom ofthe retainer 123, so that the water in the retainer 123 is surelydrained from the retainer 123 through the third through portion 127.Vehicles tilt to the front or rear during running on an uphill ordownhill slope or when the retainer 123 itself is combined to the bodyon a slant.

Preferably, for the draining structure of the embodiment in view of thesurface tension of water, the first through portions 125 have a holediameter of 7 mm or more (38 mm2 or more in section area), and thesecond through portions 126 and the third through portions 127 have thesame section area as that of the first through portions 125 or the sameslit width as the hole diameter of the first through portions 125.

Referring now to FIGS. 15 to 18, the motion of the airbag apparatus 120will be described. FIG. 15 shows the state of the airbag 121 of theairbag apparatus 120 at the start of inflation; FIG. 16 shows the airbag121 at the middle of inflation; and FIGS. 17 and 18 show the airbag 121at the completion of inflation. Specifically, FIG. 17 shows the airbag121 at the completion of inflation, viewed from the side of the vehicle;and FIG. 18 shows the airbag 121 at the completion of inflation, viewedfrom the top of the vehicle.

When the motorcycle 100 comes into a collision in the travelingdirection, the occupant is moving (flung) ahead of the motorcycle 100.In the embodiment, upon detection of the frontal collision, the inflator122 of the airbag apparatus 120 is activated to supply inflation gasgenerated by the inflator 122 into the airbag 121. This starts theinflation (deployment) of the airbag 121 in the direction of arrow 10 inthe airbag apparatus 120 of FIG. 3 in a state before activation. Sinceinflation gas is continuously fed into the airbag 121, the airbag 121 isexpanded in sequence from the retainer 123.

As shown in FIG. 15, with the airbag 121 at the beginning of deployment,the airbag 121 in the process of deployment pushes the top plate 131 ofthe module cover 130 from below in the retainer 123. Thus the modulecover 130 that has received a predetermined deploying force or more fromthe airbag 121 is torn open along the tear lines (the tear lines 133 and135) of the erect portion 132. Upon starting the deployment of theairbag 121, the webbings 140 stitched to the airbag 121 is subjected toa tensile load via the first end 141. Thus the webbings 140 pushes openthe webbing covers 107 upward to thereby release the covering by thewebbing covers 107.

As shown in FIG. 16, with the airbag 121 in the middle of deployment,the module cover 130 torn open along the tear lines further receives thedeploying force from the airbag 121 to deploy ahead of the vehicle withthe portion of the erect portion 132 adjacent to the front of thevehicle as the hinge. At that time, when a further tensile load isapplied to the webbings 140 via the first end 141, the retaining forceby the hook-and-loop fastener 144 is canceled, so that the folded stateof the folded portions 143 is released. Since the folded portions 143 ofthe webbings 140 of the embodiment are generally disposed symmetrically,the loads on the airbag 121 by the webbings 140 extending during thedeployment of the airbag 121 can be made substantially equal on theright and left, whereby the airbag 121 can deploy bilaterally evenly.

Thus, as shown in FIGS. 17 and 18, the airbag 121 is completelydeployed. In this state, the inflated airbag 121 fills the occupantrestraining region 150 in front of a rider R in FIG. 17. Thus, the riderR who is moving forward by the kinetic energy of the collision isrestrained by the airbag 121 and the impact to the rider R duringrestraint is reduced.

The webbings 140 fully extend substantially linearly between the airbag121 and the fastener 108 to restrict the motion of the airbag 121 movingupward and forward of the vehicle by the tension thereof. The fullyinflated airbag 121 comes into contact with the front portion 102 at thefront of the vehicle, and into contact with the handlebars 104 at bothsides. This arrangement stabilizes the restraint of the rider R with thefully inflated airbag 121.

According to the embodiment, the wear of the webbings 140 due to contactwith the metallic retainer 123 is prevented by the smooth surface 124 aof the bent portion 124. This improves the protection of the webbings140. Particularly, the structure of the embodiment in which the retainer123 itself in contact with the webbings 140 has the smooth surface 124 asimplifies the structure of the smoothing device, thus reducing thenumber of components.

It is to be understood that the invention is not limited to theabove-described embodiment, but various applications and modificationscan be made. For example, the following applications are possible.

The embodiment employs the smooth surface 124 a (refer to FIG. 4) of thebent portion 124 formed by folding (bending) the upper end of theretainer 123 as a smoothing device for reducing the sliding resistancebetween the contact of the retainer 123 and the webbings 140 to enablesmooth sliding. The invention may use various modifications of thesmoothing device. For example, the structure of FIGS. 19 to 21 may beadopted. FIGS. 19 to 21 show other embodiments of the bent portion 124of FIG. 4.

In the embodiment of FIG. 19, a coated portion 224 is disposed at theupper end of the metal plate of the retainer 123. The coated portion 224is formed by coating the upper end of the retainer 123 withlow-sliding-resistance resin or by bonding unwoven fabric. This coatedportion 224 has the function of reducing the sliding resistance(frictional resistance) between the contact of the retainer 123 and thewebbings 140 to enable smooth sliding. The coated portion 224 serves asthe “smoothing function” of the invention.

In the embodiment of FIG. 20, a protective cap 324 is provided at theupper end of the metal plate of the retainer 123. The protective cap 324is made of low-sliding-resistance resin. This protective cap 324 has thefunction of reducing the sliding resistance (frictional resistance)between the contact of the retainer 123 and the webbings 140, therebyenabling smooth sliding. The protective cap 324 serves as the “smoothingdevice” of the invention.

In the embodiment of FIG. 21, a cylindrically sewn protective fabric 424is provided around the outer peripheries of the webbings 140 in the areacorresponding to the upper end of the retainer 123. The protectivefabric 424 is made of low-sliding-resistance resin. This protectivefabric 424 has the function of reducing the sliding resistance(frictional resistance) between the contact of the retainer 123 and thewebbings 140 by lying therebetween as a buffer or by wearing away by theprotective fabric 424 itself, thereby enabling smooth sliding. Theprotective fabric 424 serves as the “smoothing device” of the invention.

Thus, the embodiments of FIGS. 19 to 21 can also prevent the wear of thewebbings 140 as with the bent portion 124 of FIG. 4.

The smoothing device for smoothing the sliding between the webbings andthe metallic contact of the housing in contact with the webbings may bedisposed between the webbings and the contact, at the webbingsthemselves, or at the contact itself. The contact here may be theretainer 123 itself or a member on the retainer 123, or alternatively,may be the module cover 130 itself or a member on the module cover 130.

The smoothing device of the invention may adopt a structure in which amaterial of low sliding resistance (frictional resistance) to thewebbing is disposed between the webbing and the contact, a structure inwhich an arcuate smooth contact is used, a structure in which a contacthaving a large surface area is used, or a structure in which the contactis subjected to surface grinding, thereby decreasing the slidingresistance (frictional resistance) to the webbing.

While the embodiment has been described with reference to the motorcycle100 of what is called a touring type, the invention may be applied toother types of motorcycle such as motor scooters having a space thatenables lateral movement of the rider's legs between the handlebars andthe seat and to motorcycle vehicles other than the motorcycle 100.

While the embodiment has been described about the case in which theairbag apparatus 120 is disposed in front of the fuel tank 106, theposition of the airbag apparatus 120 may be varied as appropriate,provided that the airbag 121 can deploy into a desired region in avehicle collision. For example, the airbag apparatus 120 may be disposedbehind or lower than that shown in FIG. 1.

1. An airbag apparatus comprising: a retainer assembly for housing anairbag; an opening in the retainer assembly for a tether to extendtherethrough; a guide portion of the retainer assembly adjacent theopening for guiding the tether; and a smooth contact surface on theguide portion for low friction engagement with the tether.
 2. The airbagapparatus of claim 1 wherein the guide portion includes an upstandingwall having a body of different material from that of the contactsurface.
 3. The airbag apparatus of claim 2 wherein the wall body is ofa metallic material and the contact surface is of a low-friction resin.4. The airbag apparatus of claim 1 wherein the retainer assemblyincludes a retainer base portion having a side wall including the guideportion.
 5. The airbag apparatus of claim 4 wherein the guide portioncomprises an upper end portion of the side wall of the retainer baseportion.
 6. The airbag apparatus of claim 5 wherein the retainerassembly includes a cover having depending side walls and the side wallupper end portion of the retainer base portion is spaced from acorresponding one of the peripheral side wall portions of the coverportion.
 7. The airbag apparatus of claim 5 wherein the smooth contactsurface includes an arcuate portion on the side wall upper end portion.8. The airbag apparatus of claim 5 wherein the guide portion comprises afolded wall portion of the retainer assembly to form the smooth contactsurface on the folded wall portion.
 9. The airbag apparatus of claim 1wherein the smooth contact surface includes a low friction coatingdisposed on the guide portion.
 10. The airbag apparatus of claim 1wherein the smooth contact surface is of a low-friction-resistanceresin.
 11. The airbag apparatus of claim 1 including a protective caphaving the smooth contact surface thereon.
 12. The airbag apparatus ofclaim 11 wherein the guide portion comprises a side wall of the retainerassembly and the protective cap is configured and arranged to matinglyfit on an upper end of the retainer side wall.
 13. The airbag apparatusof claim 11 wherein the protective ca p extends about the tether.
 14. Anairbag apparatus for a motorcycle, the airbag apparatus comprising: aretainer having upstanding side wall portions; a cover portion havingperipheral side wall portions depending therefrom, with at least one ofthe peripheral side wall portions secured to the retainer; an enlargedthrough hole on one of the peripheral side wall portions for a tether toextend therethrough; a lifting flange for lifting the tether in theretainer; a smoothing contact surface on the lifting flange.
 15. Theairbag housing apparatus of claim 14 wherein the lifting flange extendsupwardly above the through hole.
 16. The airbag housing apparatus ofclaim 14 wherein the smoothing contact surface is on an upper end of thelifting flange.
 17. A motorcycle comprising: a body; a seat of the bodyfor supporting a rider seated thereon; a retainer assembly mountedforwardly of the seat and having side walls and an open portion; anairbag housed in the retainer in a folded state for being deployed outof the open portion and inflated rearwardly upon detection of a frontcollision of the motorcycle; a cover portion covering the open portionof the retainer and having peripheral side wall portions dependingtherefrom, with at least one of the peripheral side wall portionssecured to the retainer; a through hole disposed on one of theperipheral side wall portions; an elongated tether that is secured atone end to the airbag, with the tether extending over a side wall of theretainer and through the through hole; and a smoothing contact surfacein the retainer assembly for low friction engagement with the tetherextending in the retainer to the airbag.
 18. The motorcycle of claim 17wherein the smoothing contact surface is disposed on an upper end of oneof the side walls of the retainer.
 19. The motorcycle of claim 17wherein the smoothing contact surface is disposed on the tether.
 20. Themotorcycle of claim 19 wherein the tether includes a cylindrical tube ofprotective fabric surrounding a portion of the tether with the tubeincluding the smoothing contact surface.
 21. The motorcycle of claim 20wherein the cylindrical tube surrounds a portion of the tether thatextends and moves over an upper end of one of the side walls of theretainer.